diff --git a/setup.py b/setup.py
--- a/setup.py
+++ b/setup.py
@@ -741,12 +741,9 @@
 
                 # Copy the pythonXY.dll next to the binary so that it runs
                 # without tampering with PATH.
-                fsdecode = lambda x: x
-                if sys.version_info[0] >= 3:
-                    fsdecode = os.fsdecode
                 dest = os.path.join(
                     os.path.dirname(self.hgtarget),
-                    fsdecode(dllbasename),
+                    os.fsdecode(dllbasename),
                 )
 
                 if not os.path.exists(dest):